curvature versus slope
  n = 47952 
  X=0, Y = 48.47 +/- 22.99 
  Weighted least-squares fit:  Y = 59.4 + 2.020 X  + -0.02215 X**2 

slope versus dZ, curvature < 5
  n = 20521 

  Weighted least-squares fit:  Y = 0.7 + 1.014 X  + -0.00177 X**2 
     at X = 100, Y = 84.3 
     effective RMSE xy = 132.5 

slope versus dZ, curvature < 15
  n = 34531 

  Weighted least-squares fit:  Y = 1.7 + 1.019 X  + -0.00173 X**2 

curvature versus dZ, slope < 10
  n = 327 
  X=0, Y = 15.05 +/- 11.24 
  Weighted least-squares fit:  Y = 14.2 + 2.665 X  + -0.43009 X**2 


Number of samples 48392
Max dz = 900
Mean dz = 63
RMS dz = 164.085343648
100cm = 88.7998016201 percentile value of dz